A trough of low pressure was moving inland across San Diego County Sunday and was forecast to bring cooling through Tuesday, the National Weather Service said.
Daytime highs were forecast to be below average for much of the week, with the coolest day on Monday, meteorologists said.
Highs on Monday were forecast to be 64 to 69 along the coast, 66 to 71 inland, 68 to 78 in the mountains and 94 to 99 in the mountains.
The marine layer was expected to be deepest Monday night into early Tuesday morning.
Westerly winds were forecast to bring gusts of 35-50 mph near and below the mountain passes, and into the deserts for the next several days, combined with minimum relative humidity values of 10-20%. These conditions were expected to create elevated fire weather conditions at times.
By the end of the week, highs will be close to average, with further warming into early next week as the trough weakens, the weather service said.
— City News Service contributed to this article